Maize is one of the widely distributed cereals in the world. In fact, maize has become a staple food in many parts of the world with total production of maize surpassing that of wheat and rice. Maize farming is therefore very popular among farmers worldwide. However, in spite of its popularity, it is an expensive and difficult crop to grow. For this reason, it is important to have an in-depth knowledge of how it is grown so as to achieve good yields from the onset.
The ideal climate for maize farming is a warm weather with moderate rainfall. Maize crop requires temperatures around 21oC to 27oC and rainfall of about 500mm to 600mm in temperate areas. Depending on the rate of evaporation in extremely dry areas, water usage may go up to 900mm or more. The uptake of water in maize farming increases gradually from germination to the vegetative growth stage. Water shortages during this period risks successful flowering and fertilisation. 20oC is needed for maize germination, however, it can occur in temperature below this range. Still, the successful crop growth will need higher temperatures. The critical temperature destructively affecting yield is approximately 32oC. Front is also detrimental to maize and so a frost-free period of 120 to 140 days is required.
Maize grows best in rich loam or sandy-loam soils, in a well-drained area that has a flat or fairly flat landscape. Free draining medium loams enable young plant to grow well, however, farmers should take note that their soil is not too light and free-draining like sand soils as they hinder successful plant growth. The soil should have effective depth, favourable morphological properties, good internal drainage, an optimal moisture regime, sufficient and balanced quantities of plant nutrients and chemical properties that are favourable specifically for maize farming. Maize is reasonably tolerant to soil acidity, but if the soil is very acid, applying lime will improve it and enhance maize yields. Since maize farming is affected both drought and waterlogging, ridge tillage, drainage system and early planting can be applied for a successful harvest. In drier areas, soil and water conservation techniques such as mulching should be employed especially during the four week period spanning flowering.
Seed variety is an important aspect of maize farming. The choice of seed depends on the yield potential, season length, anticipated disease problems and usage. For high stable yields, farmers should select improved varieties that have the appropriate agronomic strengths for the environment. Some hybrids take about 140 to 155 days to mature whereas others mature within 120 to 140 days depending on air temperature. Maize takes longer to mature in cooler temperatures. It is recommended that farmers select a seed variety that they are experienced with and when using a new variety, adequate knowledge should be acquired before the planting season begins. The total amount of seeds required vary with regards to production purpose, seed variety and sowing method. When choosing seed variety, the following has to be considered:
- altitude and air temperature
- soil fertility and fertiliser application
- planting date
- plant density
- use (commercial grain, green mealie and silage)
- occurrence of pests and diseases
Maize grows well when planted in ridges as the ridge farrow system provides adequate moisture and air ratio in the root zone. When planting on a flat surface, the crop should be tilled immediately after the 2nd top dressing of nitrogen which should be approximately 4 weeks after planting. When using the zero-tilling system for maize farming, 30 % of the soil must be covered with plant residue after planting to reduce water erosion effectively. The maize seeds have to be planted in rows, however the space between the rows depends on the type of maize. For successful maize farming, seeds ought to be sown about 0.5cm deep to allow effective germination. In case of poor germination, gap-filling can be used.
The fertiliser requirements in maize farming is contingent on the soil fertility, yield target, previous cropping history and the maturity group of the hybrid. Infertile soils require more fertiliser to improve the soil nutrients, as does a higher yield target. Maize responds well to the application of organic manure for example crop residue, which improves the physical conditions of the soil as well as its water retention capacity. Inorganic fertilisers can be added in as supplement to organic fertilisers. A combination of both organic and inorganic fertilisers enhances soil fertility producing higher yields. The fertilizer dosage used in maize farming is based on the soil fertility information obtained during soil tests that are usually done at least once every five years. Soil testing helps to determine the exact amount of fertiliser required thus avoiding under and over fertilization. Depending on soil fertility status, hybrid maturity and soil type, approximately 150-180 kg nitrogen, 40-80 kg phosphorous, 160-180 kg potassium and 10 kg zinc per ha is recommended for maize crop. Note that full season hybrids require a higher fertiliser dosage compared to early maturing hybrids.
Controlling weeds is very important in maize farming. Maize is very poor at competing with weeds in its earliest stages of development and so weed must be removed while ploughing and harrowing. Ideally, weeding should be done between 8 to 10 weeks as crops emerge from the ground. Farmers can either employ the hoeing technique or purchase herbicides depending on the size of the farm. Mulching is helpful in controlling weeds.
Pests and Diseases
Pests and diseases including stem borers, army worms, grasshoppers, larger grain borers, downy mildew, maize streak virus and Striga among others are a big challenge in maize farming. Seed varieties that are resistant or can tolerate pests in an environment should be selected hence the need to be knowledgeable about seeds varieties before planting. Maize rotation with legumes can help with reducing weed, insect and disease pressure, enhancing soil fertility and improving yields. The field should be inspected and closely monitored for pest infestation from as early as the seeds emerge. Pesticides should be applied quickly in case of an outbreak.
The harvesting time depends on the maize variety. Maize matures after 80-160 days depending on the variety. Read more information on harvesting maize. Although maize farming is quite common, a large number of farmers fail to achieve the best possible yields costing them a lot of time and money. Farmers need to be cautious and pay close attention to their maize crops when practising maze farming. They also need to have adequate knowledge on maize farming techniques versus their environment, also taking into consideration their choice of maize variety in order to achieve high yields.